The transport of particulate material sometimes requires that a relatively spiked, uneven flow of particles be leveled out to a more even flow condition prior to the particles being delivered to a destination. An example of this situation occurs in connection with recently developed thermal energy production, storage and reclaim systems where an ice machine is utilized to produce ice particles that are conveyed to a thermal energy storage tank that stores the ice. In these systems the ice particles discharged from the ice machine are entrained in a transport water and transported to the thermal energy storage tank. A primary purpose of this thermal energy production, storage and reclaim technology, as discussed in detail in commonly assigned U.S. Pat. Nos. 5,046,551; 5,063,748; and 5,195,850, incorporated herein by reference, is to permit a low power prime mover in the form of an ice machine to be used continuously to produce ice, to store the energy in the form of ice and thereafter withdraw the energy in large quantities when needed. With such a system in place at an installation with high peak time power requirements, the power company has the advantage of providing power continuously to a relatively low power, level load instead of having to meet very high energy demands at peak load periods. More particularly, the above-mentioned commonly assigned patents describe a thermal energy production, storage and reclaim system wherein ice is produced primarily at off-peak times by a vapor compression ice making machine and delivered entrained in a transport water by a sluice conduit to a relatively large thermal energy storage tank. In particular embodiments, the ice is delivered to a point near the bottom of the thermal energy storage tank through a hopper and downpipe arrangement that overcomes the problems associated with delivering a buoyant particle to the bottom of a flooded vessel. The ice particles so introduced into the storage tank agglomerate into a submerged ice mass that generally takes the shape of an inverted cone.
In addition to the above-mentioned problems associated with the transport of buoyant particles such as ice particles, an additional problem has emerged with respect to the use of conventional ice machines. It is well known that many ice machines, rather than delivering ice on a continuous discharge basis, discharge ice in large "slugs" over relatively short spans of time so that there are considerable periods of time during which no ice or little ice is being discharged by the ice machine. This batch ice delivery is a type of spiked, uneven flow condition and presents a problem with respect to matching the ice machine discharge rate with the flow rates that can be accepted by the sluicing system hoppers and downpipes. Stated differently, if the large slugs of ice were to be directly introduced into the sluicing system and thermal energy storage tank without reducing the spikes in the flow rate, the ice slugs would overwhelm the capacity of these delivery systems. Thus, there is a need for a system to level out the spiked, uneven flow rate created by the ice machine to a more even flow condition consistent with the capabilities of the sluicing lines and downpipe delivery system to the thermal energy storage tank.
One proposed solution to the above problem is to use mechanical augers to deliver the ice to the thermal energy storage tank. However, the augers are mechanical systems subject to breakdown. Furthermore, the motors of augers use substantially more energy than the pumps of a comparably sized hydraulic conveyance system. In addition to these disadvantages, and more important, an ice-in-water, two-phase flow regime in the augers can easily result in a bridging of the two-phase system into an almost solid ice mass which would prevent the auger from moving ice. Stated differently, the ice and water mixture in the auger, under certain conditions, can freeze into a solid mass, thereby "clogging" the auger and rendering it useless.